How to correctly write a regular expression replacing the exact number of characters?

Question

ruby

There is a regular expression that replaces everything before @ with [email protected] I would like it to be replaced not just with "[email protected]" but with the exact number of characters, tell me how to do it right about the great ones !!!

def protected_email
    self.email.gsub /[^@]*@/, '[email protected]'
  end

Answer 1

.gsub(/[^@](?=.*[email protected])/, ?x)

Answer 2

Open the documentation for the Regexp class, read distributed Repetition